Tracker-bar for pneumatic musical instruments.



W. G. BETZ. TRACKER BAR FOR PNEu iATTc MUSICAL INSTRUMENTS. APPLICATION FILED OCT. 10. 1914- 1,208,275. Patentgd Dec. 12, 1916.

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WILLIAM G. BETZ, OF BUFFALO, NEW YORK.

TRACKER-BAR FOB PNEUMATIC MUSICAL INSTRUMENTS.

Specification of Letters Patent.

Patented Dec. 12, 1916.

Application filed October 10, 1914. Serial No. 866,001.

To all whom it may concern Be it known that I, WILLIAM G. Bn'rz, a citizen of the United States, residing at Buffalo, county of Erie, and State of New York, have invented certain new and useful Improvements in Tracker-Bars for Pneumatic Musical Instruments, of which the following is a specification.

My invention relates to tracker bars for pneumatic musical instruments and is directed more particularly to the air ports thereof, an object of my invention being to provide an improved port construction whereby a more effective action may be obtained.

In player pianos and like instruments there is difficulty in maintaining the music perforations and tracker bar ports in such relation as to always provide the best operation of the valve mechanism. This trouble arises because of the lateral shifting of the music sheet so that the perforations thereof do not always register properly with the port on account of the port being very little wider, if any, than the perforations. The port centers of course are fixed because of the standard construction of pianos and the perforations in the music must be of suitable width and have a substantial amount of wall between them.

In order to provide a more effective control port construction and still maintain standard centers, I arrange the ports so that there is practically no vertical clearance between them thus first of all allowing for a greater lateral variation of the music perforations. The side walls are preferably vertically disposed and the upper and lower walls or edges are oblique but parallel or substantially so so that the lower corner of one side of the port is above the upper corner of the adjacent side of the next port. The shape of the port is thus preferably rhomboidal. An important feature of this construction is that no matter where the perforations pass over the port thepressure is the same and thus the pneumatic action is the same, and air is admitted and shut off simultaneously on even chords.

For a better understanding of my invention reference will be made to the accompanying drawing in which Figure 1, shows my improved tracker bar in connection with a sheet-music holding device; Fig. 2 is a sectional view of Fig. 1;

and Fig. 3 is an enlarged portion of the tracker bar and music sheet.

The music holding device illustrated is a standard form and comprises a music roll 1 and winding roller 2 together with a music sheet 3 which passes over the tracker bar 4. The ports A preferably have parallel vertical side edges or walls 5, 6, and parallel oblique upper and lower edges or walls 7 8. I preferably arrange the lower corner of the side edge 5 above the upper corner of the side edge 6 of the adjacent port, thereby providing a substantial wall 9 between the ports. It will be evident from this construction that greatest width of port with upper and lower parallel edges is permitted, on given centers. That is, without overlapping the ports.

In sheet music, short notes, as 10, are frequently placed as close as possible, their centers being determined by the space between them necessary to close the port. In such case it is important, on chords principally, that the action be not only simultaneous, but that the registration of the port and perforation will be such as will allow the same valve action on each note. With my improved port such control is provided up to the limit of the lateral variation of port and perforation. From an inspection of Fig. 1, it will be seen that even chords have their notes simultaneously started and shut off no matter over what part of the port the perforations pass.

In Fig. 1 the left portion of the music sheet has its perforations passing over the left side of the ports and the right portion of the music sheet has its perforations passing over the right side of the port thus illustrating the manner in which lateral varia tion is permitted without interfering with a. proper registration of ports and perforations.

Having described my invention, what I claim as new and desire to secure by United States Letters Patent, is:

1. An elongated horizontally disposed tracker bar for pneumatic players having ports provided with upper and lower edges oblique to the horizontal axis of the bar and extending in the same general direction, and vertically disposed side edges directly connecting the upper and lower edges.

2. An elongated horizontally disposed tracker bar for pneumatic players having 1 edges, a side edge of each port being positioned above the adjacent side edge of the next port.

4. A. tracker barfor pneumatic players having a horizontal row of similarly shaped and similarly disposed ports covering the full centers from port to port and provided with oblique upper and lower substantially parallel edges and connecting side edges, a side edge of each port being positioned above the adjacent side edge of the next port. i

Signed by me at Chicago, COHIlty of Cook and State of Illinois, in the presence of tWo Witnesses.

WILLIAM G. BETZQ Witnesses GEORGE E. MUELLER, THOMAS MARSHALL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). G. 

